In the history of mankind, there have been many brilliant thinkers who are pragmatic, fearless and even brave in dedication, and have made outstanding contributions to the treasure house of human knowledge. Their theory is undoubtedly an important ideological source of Marxism. However, there has never been such a theory as Marxist theory, which combines strict scientific nature with high revolutionary nature. The emergence of Marxism has achieved great changes in the history of human thought. The significance of this change lies in: first, Marxism has a distinct class nature, which organically combines class nature with objectivity. In the past, all social science theories were limited by the class it represented to varying degrees, and could not completely reveal the laws of the development and change of the objective world movement. Marxism is the ideological weapon of the proletariat, the most progressive, revolutionary and promising class in history. It reflects the fundamental interests and demands of the proletariat and guides the great struggle of the proletariat for the liberation of all mankind. The class status and historical mission of the proletariat not only have the possibility and necessity to thoroughly understand and apply the objective law of social development, but also the more comprehensive and profound the understanding of this law, the more correct and thorough the application, the more in line with the fundamental interests of the proletariat. The increasingly close combination of Marxist scientific theory and the proletarian movement has opened up a magnificent history and prospect of the international proletarian movement. Second, Marxism has a strong practicality, organically combining practicality with theory, revolutionary transformation of the world and scientific understanding of the world. In the past, all social science theories were divorced from social practice to varying degrees, and there was a fundamental shortcoming that theory was divorced from practice. Marxism, on the other hand, takes social practice as the basis and motive force for its emergence and development, takes serving social practice as its purpose, constantly accepts the test of practice, and always maintains the closest contact with social practice, so it can become the spiritual weapon for the proletariat and the broad masses of working people to understand and transform the world, while maintaining the vitality of the theory itself. Third, Marxism is a scientific criticism and an organic combination of criticism, inheritance and development. In the past, all social science theories were limited by their own wrong viewpoints, methods and systems to varying degrees, which often stifled the development of science and prevented people from revealing objective truth in depth. On the other hand, Marxism is different. It integrates inheritance and transformation, revolutionary criticism and theoretical creation, scientific content and strict and open system. It does not recognize anything eternal, denies any dogmatism, does not give in to all superstitions, heresies, idealism and metaphysics, does not give in to any reactionary conservative forces, follows the law of dialectical development, constantly opens up the road to understanding the truth, and never stops approaching the objective truth and marching into the free kingdom. The emergence of Marxism not only opened a new stage of the international proletarian movement, but also opened a new era of social science development.